Technical Field
The present invention relates to a fluid control valve assembly adapted for use in a thermostat valve device that switches the flow of a coolant according to the coolant temperature, in a cooling device for an internal combustion engine for an automobile, for example (hereinafter “automobile engine”).
Description of the Background Art
In automobile engines, for example, a water-cooled cooling device employing a radiator is commonly used to cool the engine. Conventionally, in a cooling device of this type, a thermostat valve device employing a thermal expansion unit that adjusts the amount of coolant circulated to the radiator side is used to be able to control the temperature of the coolant introduced into the engine.
More specifically, the thermostat valve device using the thermal expansion unit is mounted at one portion of the coolant flow path, such as the engine intake side. To adjust the temperature of the coolant to the required state, when the coolant temperature is low, the thermostat valve device closes the control valve and circulates the coolant through a bypass flow path without passing through the radiator, and when the coolant temperature is high, the thermostat valve device opens the control valve and circulates the coolant through the radiator.
Conventionally, a variety of structures are known for this type of thermostat valve device, such as that shown in JP-H02-011289-U, for example.
Briefly, in this thermostat valve device, the installation position of the device within the engine cooling system is a fluid confluence where the coolant flow path from the radiator intake and the flow path from the bypass flow path from the engine outlet and further to the engine intake come together. To solve the problem of inaccuracy in the temperature detection at the thermostat temperature sensitive part provided facing the interior of the fluid flow path due to disturbances in the flow of coolant and unevenness in temperature of the coolant that arises therefrom, this invention forms irregularities along the fluid flow path in the wall on which the thermostat temperature sensitive part is mounted to revolve the fluid tactilely and churn it, making the coolant temperature uniform.
However, with the conventional thermostat valve device as described in JP-H02-011289-U, a loss of pressure due to disturbance of the flow of fluid through the fluid flow path where the thermostat valve device is installed is unavoidable. To secure a predetermined supply flow volume it is necessary to increase the fluid pressure, which in turn causes other practical problems such as an increase in the size of the pump or other compressor means and in the overall size of the apparatus.